This invention relates to sterilization wrap. More particularly, it relates to sterilization wrap utilizing two layers or sheets of material.
Reusable medical instruments must be sterilized prior to each use. Normally, these instruments are exposed to a sterilant to achieve sterilization. As used herein, the term sterilant is meant to refer to the sterilization effectors that are conventionally utilized with sterilization wrap, sterilization techniques, including but not limited to steam, ethylene-oxide, plasma, or the like. In order for the instruments to remain sterile after the sterilization procedure, the instruments must be wrapped in a material called sterilization wrap prior to the sterilization procedure.
The most common type of sterilization wrap is a three-ply laminate consisting of a layer of melt blown polypropylene sandwiched between two layers of spunbond polypropylene. The wrap includes bond points all across the face of the material so that the material is held together, i.e., laminated. This three-ply material is commonly referred to as “SMS”, which is short for spun bond-melt blown-spun bond. Most hospitals specify SMS as the sterilization wrap to be used because SMS is sufficiently porous to permit steam, ethylene-oxide and other sterilization materials to penetrate through the material to the surgical instruments, but has filtration properties sufficient to prevent the passage of most pathogens therethrough so as to maintain sterility after the sterilization process. The wrap also protects articles during sterilization, and acts as a filtration medium for the sterilant.
In most hospitals, there is a protocol which requires surgical instruments to be wrapped with two separate sheets of material so that if one sheet becomes torn, there is a redundancy which will maintain the sterility of the surgical instruments. The wrapping of surgical instruments with two separate sheets of sterilization wrap obviously is labor intensive in that the clinician must first place the instruments on one sheet of sterilization material and wrap the instruments, and then place the wrapped package on another sheet of sterilization material and again wrap the package containing the instruments.
In an attempt to reduce the labor required to provide dual wrapping of surgical instruments, Kimberly-Clark Corporation has developed a product called “One Step® Sterilization Wrap.” One Step® Sterilization Wrap is made by bonding two separate sheets of sterilization wrap together near two of the edges of the adjacent sheets. The Kimberly-Clark One Step® product is described in U.S. Pat. Nos. 5,635,134 and 5,688,476.
FIG. 1 herein shows one of the Kimberly-Clark One Step® products described in these Kimberly-Clark patents. Sterilization wrap 10 includes a top sheet 12 made of SMS and a bottom sheet 14 also made of SMS. The lengths and widths of top sheet 12 and bottom sheet 14 are identical and the outside edges of each layer align with one another. The two layers of SMS are bonded together near two opposing edges 16 and 18, as illustrated by bond lines 20 and 22. The method of bonding the two sheets together may be ultrasonic bonding. The other two opposing edges 24 and 26 are not bonded together so there is a visible gap 28 between sheets 12 and 14 so that the user of the sterilization wrap visually distinguishes the fact that there are, indeed, two sheets. Apparently the purpose for ensuring that the two sheets are visually distinguishable as separate sheets is so that the user knows with certainty that the item to be sterilized has two sheet protection. However, because of this gap 28, debris could enter the region between the two sheets. With two of the edges being unbonded, it is possible that the sheets become misaligned so that if a sharp object penetrates both sheets, the resulting holes in each sheet could also become misaligned, thus reducing ones ability to determine whether or not there is a hole through both sheets. In addition, since edges 24 and 26 are not bonded and bond lines 20 and 22 are somewhat removed from edges 16 and 18, fibers from those edges could become released from the wrap. Also, since the edges 24 and 26 are not bonded, the two sheets might be pulled apart by mistake during use. Furthermore, since the wrap shown in FIG. 1 is not sealed right to the edges 16 and 18, the user might perceive that there could be contamination between the sheets.
Recently Cardinal Health has introduced a new two sheet sterilization wrap called Simul-Wrap® which overcomes the problems of the Kimberly-Clark One Step® product described above. The Simul-Wrap® product is made of two identical sheets of SMS sterilization material which are bonded together along all four edges. The Cardinal Health Simul-Wrap® product is shown in U.S. Pat. No. 6,517,916. However, both the One Step® product and the Simul-Wrap® product have certain drawbacks. Neither product is specifically engineered to wick moisture away from the article to be sterilized after sterilization takes place. In addition, neither product provides an indication that adequate sterilization has been achieved.